What is Skype up to?

[Captain K]

Noticed recently that the lights on my router were indicating network activity, on the port my main PC is connected to (by network cable), but no apps were running other than those sitting in the system tray.  Looking at the resource monitor reveals that Skype is sending and receiving significant amounts of data - screenshot below.



This normally happens about 10-15 minutes after I switch the PC on, and lasts for about 20 minutes.  I use Skype a lot to communicate with friends abroad, and its one of the few apps I allow to run at startup.  The IP address shown in the resource monitor changes every time - a quick Sam Spade treatment on the IP address shown tells me its Qatar Petroleum!

I have none of the automatic update options ticked, so it shouldn't be downloading anything.  A fall Spybot and AV scan reveals nothing of concern.

After this spurt of activity, nothing further happens for the remainder of the time the PC is switched on.

Anyone have any idea?  Am I missing something blindingly obvious?

[Rik]

Does this help, Bruce:

"Skype protocol

    Main article: Skype Protocol

Skype uses a proprietary Internet telephony (VoIP) network. The protocol has not been made publicly available by Skype and official applications using the protocol are closed-source. The main difference between Skype and standard VoIP clients is that Skype operates on a peer-to-peer model rather than the more usual client-server model. The Skype user directory is entirely decentralized and distributed among the nodes of the network—i.e., users' computers—which allows the network to scale very easily to large sizes (currently about 240 million users)[26] without a complex centralized infrastructure costly to the Skype Group."

http://en.wikipedia.org/wiki/Skype

[Captain K]

Thanks Rik! 

So its just me (and 240 million other users) saving Skype the cost of a central infrastructure!  Fair enough I suppose for free software.

[Rik]

It looks like it, Bruce.

[Dangerjunkie]

Hi,

If you have two Skype users behind NAT or firewalls they can't talk to each other as neither side could initiate a connection. If Skype has unrestricted access in your computer Skype gets round the connection problem above by volunteering your computer (and bandwidth) as a relay do NATed/firewalled users can talk to each other. You have no choice about this behaviour and can't suppress it if you have limited transfer or you pay per MB for your transfer.

What you saw was probably someone else's file transfer or call but since it was encrypted you have no way of knowing.

Cheers,
Paul.

[Captain K]

That's very interesting, and seems appropriate as well, as the data incoming rate was roughly the same as the outgoing rate.  However, I'm behind a NAT router as well - should it still be possible?

[Niall]

This is why a lot of people stopped using Skype. I can't remember if they've always done it, or it started being done a while after release. What I do remember is that a lot of people didn't know they did it at all, but not on the sneaky little git method that Sky used, when claiming it was #10 in their list informing you of this. This was where you had a list that contained 1 to 16 (or something like that) and number 10 was missing. Sky are bad, mkay?

[Dangerjunkie]

Hi,

That's very interesting, and seems appropriate as well, as the data incoming rate was roughly the same as the outgoing rate.  However, I'm behind a NAT router as well - should it still be possible?

If your router supports UPNP (Universal Plug aNd Play) and you have it turned on then if Skype is UPNP-aware Skype (or any other UPNP application) could open almost any port it desires on your firewall/NAT. I haven't looked into it but if I wrote Skype I would have put UPNP into it.

Cheers,
Paul.

[Captain K]

Well, it doesn't seem to take up too much bandwidth, and since I'm only hovering at around 50%-55% of my 30GB monthly usage, I'll leave it alone for now, but I'll certainly keep an eye on it.

Thanks Paul. 

[Tacitus]

If your router supports UPNP (Universal Plug aNd Play) and you have it turned on then if Skype is UPNP-aware Skype (or any other UPNP application) could open almost any port it desires on your firewall/NAT.

IMHO UPnP is a disaster waiting to happen, since I would have thought it relatively simple for a hacker to construct a UPnP aware malware app and use it to target someone.  One reason I always have it turned off and avoid anything which claims to be UPnP 'aware'.

[Rik]

I agree. It's one of the first things I disable on a new machine.

[Captain K]

I suppose it comes down to sensible management of your machine.  Provided you don't let anything in which might make malicious use of it, there shouldn't be a problem.  This is of course why my son is strictly banned from downloading anything on his PC without my specific permission.  The problem arises of course with the masses who aren't so cautious.  I regularly go and see my dad for the specific reason of disinfecting his PC of something! 

[Rik]

I regularly go and see my dad for the specific reason of disinfecting his PC of something! 

Been there...

[Captain K]

You mean my dad called you as well? 

[Rik]

Didn't he tell you?? 

[Captain K]

Considering the state of his PC, he'd clearly been getting dodgy advice from somewhere.  All starts to make sense. 

[Rik]

 

[Niall]

I agree. It's one of the first things I disable on a new machine.

I disable it on PCs I build too. That and any automated service, along with anything that has the ability to allow registry editing remotely.